GHSU approach could boost vaccine in prostate cancer

A unique approach to knocking down tumor defenses being developed at Georgia Health Sciences University could help boost a vaccine against prostate cancer and might lead to other cancer therapies, a researcher said.

That could be especially important to Augusta and Georgia because of the higher toll that prostate cancer takes among blacks, said GHSU Cancer Center Director Samir N. Khleif, who developed the potential therapy.

The university has opened a clinical trial involving Provenge, the only therapeutic cancer vaccine yet approved by the U.S. Food and Drug Administration.

The patient’s immune cells are taken out, cultured to recognize a prostate cancer protein, and then given back in a series of treatments.

The treatment is intended for those with advanced prostate cancer who already have had therapy and are not responding to hormonal therapy. It has been shown to prolong survival by a little more than four months.

“This is good because these are incremental changes, but they are small incremental changes,” Khleif said. The problem is, the tumor has developed what he calls a “tumor immune regulatory network, where the tumor is really through a network having multiple levels of strategies inhibiting the immune response,” Khleif said.

His lab is looking at an antibody that, when used in combination with the chemotherapy drug cyclophosphamide, inhibits a mechanism that tells T cells, which help in immune response, to go to sleep, which is a key part of the strategy.

Researchers must disrupt more than one tumor defense mechanism, which allows for an immune-boosting response for the immune cells rallied against the tumor, Khleif said.

He said that provides “a better environment with less obstacles (for the vaccine) to work and it also provides them a better environment to come to the tumor itself.”

The clinical trial using the GHSU potential therapy is exactly what Khleif is trying to promote at the cancer center.

“It is homegrown,” he said. “We discovered it, we developed it, we went forward with it.”

It is also a unique offering.

“This kind of trial, you don’t have it at other places in the country,” Khleif said. “People might come from other places outside Augusta to get this kind of therapy. It provides patients with an alternative therapy that they cannot get easily in this town or other places.”

The potential therapy is of particular concern for Augusta and Georgia because the death rate from prostate cancer in blacks is more than twice the death rate among whites, according to the American Cancer Society.

“This is why a therapy like this for the patients in Georgia and the citizens of Georgia would be very important,” Khleif said.